JPH03114892A - Thermal transfer recording material and forming method of picture - Google Patents

Abstract

PURPOSE:To improve heat resistance, light resistance, fixing performance, thermal diffusivity, chelating properties and a hue by forming a heat-sensitive layer including a specific dyestuff onto a support. CONSTITUTION:A heat-sensitive layer containing a dyestuff shown by formula I is formed onto a support. In formula I, X represents an atomic group required for forming the nitrogen heterocycle of a five-membered ring or a six-membered ring having aromaticity, and the nitrogen heterocycle may have a substituent group and the ring may form a fused ring with another carbon or a heterocycle. Y represents a halogen atom, an alkyl group or an alkoxy group, (n) 0, 1 or 2, R<1> a hydrogen atom or the alkyl group, and R<2> and R<3> the hydrogen atom, the alkyl group or an aryl group separately independently, and these R<2> and R<3> may bond mutually and form the heterocycle of the five-membered ring or the six-membered ring. Accordingly, heat resistance, light resistance, fixing performance chelating properties, thermal diffusivity and a hue are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer material and an image forming method, and more particularly to a novel thermal transfer material that provides a magenta dye image with excellent spectral characteristics, heat resistance, and fixability. The present invention relates to a material and an image forming method using the thermal transfer material.

[Background of the Invention] Color recording techniques such as inkjet, electrophotography, and thermal transfer are being considered as methods for obtaining color hard copies.

Among these, the thermal transfer method in particular has advantages such as ease of operation and maintenance, miniaturization and cost reduction of the device, and low running costs.

In this thermal transfer method, a transfer sheet (also referred to as a thermal transfer material) having a meltable ink layer on a support is heated by a thermal head, and the ink is transferred onto a transfer sheet (also referred to as an image receiving material). A method of melt transfer and a thermal diffusion method in which a transfer sheet having an ink layer containing a heat-diffusible dye (sublimable dye) on a support is heated by a thermal head to transfer the heat-diffusible dye to a transfer sheet. There are two types of FFI transfer methods (sublimation transfer method), but this thermal diffusion transfer method controls the gradation of the image by changing the amount of dye transferred according to changes in the thermal energy of the thermal head. This is advantageous for full-color recording.

By the way, in thermal transfer recording using the thermal diffusion transfer method,
The dye used in the heat-sensitive transfer material is important, and conventional dyes have the disadvantage that the stability of the resulting image, that is, the light fastness and fixing properties are poor.

In order to improve this point, JP-A-59-78893,
No. 59-109394 and No. 80-2398 disclose an image forming method in which a chelatable heat-diffusible dye is used to form an image of the chelated dye on an image-receiving material.

Although this method is an excellent method for improving light fastness and fixing properties, the magenta dye disclosed in this publication is not necessarily satisfactory in terms of dye diffusivity, chelation property, and hue. However, further improvements were desired.

Therefore, from the above-mentioned viewpoint, the present inventors continued various studies on dyes for thermal transfer materials and image forming methods using the same, and as a result, unexpectedly, the dye of general formula [I] was found. The present invention has been completed based on the discovery that it satisfies the conditions and is particularly excellent in diffusivity, chelating property, and hue.

[Objective of the Invention] Therefore, the object of the present invention is to improve heat resistance, light resistance, and fixing properties among the above-mentioned properties, as well as thermal diffusivity, chelating property, and hue (less undesired absorption, and An object of the present invention is to provide a thermal transfer material using a chelatable heat-diffusible dye, which has an improved image (image formed by a chelate dye having a narrow absorption band width), and an image forming method using the heat-sensitive transfer material.

[Structure of the Invention] The objects of the present invention are as follows: 1) A heat-sensitive transfer recording material characterized by having a heat-sensitive layer containing a dye represented by the general formula [I1] on a support.

General formula [I1 [wherein, Furthermore, the chain ring may form a condensed ring with another carbocycle or heterocycle, Y represents a halogen atom, an alkyl group, or an alkoxy group, and n is 0.
．． Represents 1 or 2.

R1 represents a hydrogen atom or an alkyl group, R2R3 each independently represents a hydrogen atom, an alkyl group, or an aryl group, and R2 and R3 are bonded to each other to form a 5-membered ring to
2) A heat-sensitive transfer material having a heat-sensitive layer containing at least a dye represented by the general formula [I] on a support is transferred to image information from the back side of the support. This was achieved by a thermal transfer image forming method characterized by forming an image using a chelate dye by heating the image-receiving material accordingly and reacting the dye with the dye in the presence of metal ions on the image-receiving material.

General formula [Nc In the formula, Furthermore, the chain ring may form a condensed ring with another carbocycle or heterocycle, Y represents a halogen atom, an alkyl group, or an alkoxy group, and n is 0.
．． Represents 1 or 2.

R' represents a hydrogen atom or an alkyl group, R2R3 each independently represents a hydrogen atom, an alkyl group, or an aryl group, and R2 and R3 are bonded to each other to form a 5-membered ring to
A 6-membered heterocycle may be formed.] The present invention will be described in more detail below.

In the general formula [I], X is a 5-membered ring having aromaticity -
Represents an atomic group necessary to form a 6-membered nitrogen-containing heterocycle, and examples of the nitrogen-containing heterocycle include a pyridine ring, a torimishin ring, an imidazole ring, and a virole ring. Preferably, pyridine It is a ring.

The halogen atom represented by Y is preferably a chlorine atom, a fluorine atom, etc., and the alkyl group is preferably % C1
~C4 alkyl group, such as methyl group, ethyl group, n-
A butyl group is preferred, and the alkoxy group is %CI~C
Preferred are alkoxy groups of No. 4, such as methoxy, ethoxy, propoxy, and butoxy groups.

R1 is a hydrogen atom or an alkyl group, and the alkyl group is preferably a C1-C4 alkyl group, such as a methyl group, an ethyl group, a propyl group, or a butyl group.

R2R3 each independently represents a hydrogen atom, an alkyl group,
represents an aryl group, and this alkyl group is a C3 to C6 alkyl group, such as a methyl group, an ethyl group, a n-propyl group,
An n-hexyl group is preferred, and a phenyl group is preferred as the aryl group.

Each of X and R' R3 substituted on the ring may have a substituent, and examples of this substituent include an alkyl group (e.g., methyl group, ethyl group, trifluoromethyl group, etc.), an aryl group (e.g., phenyl group, etc.). group, etc.), alkoxy group (e.g., methoxy group, ethoxy group, etc.), amino group (e.g., methylamino group, ethylamino group, etc.), acylamino group (e.g., acetyl group, etc.), sulfonyl group (e.g., methanesulfonyl group, etc.), alkoxy carbonyl group (e.g. methoxycarbonyl group), cyano group, nitro group, halogen atom (
Examples include chlorine atoms, fluorine atoms, etc.).

Next, typical compound examples of the dye represented by the general formula [I] used in the present invention will be shown, but the present invention is not limited thereto.

The method for synthesizing the dye used in the present invention is described in the margin below.
It is disclosed in Japanese Patent No. 17436.

The thermal transfer material of the present invention can be prepared by preparing an ink containing the dye by dissolving the dye together with a binder in a solvent or dispersing it in the form of fine particles, and applying the ink onto a support and drying it. A layer or a heat-sensitive layer is obtained.

The amount of the dye used in the present invention is preferably 0.1 to 20 g per m2 of support.

The image forming method using the heat-sensitive transfer material obtained in this way involves preparing the image-receiving material, aligning the heat-sensitive layer and the image-receiving layer surface, and then applying heat from the back side of the support of the heat-sensitive transfer material according to the image information. When applied, the dye corresponding to this thermal image diffuses into the image-receiving layer, where the dye is fixed and a dye image is obtained.

The binder includes water-soluble polymers such as cellulose, polyacrylic acid, polyvinyl alcohol, and polyvinylpyrrolidone; organic solvent-soluble polymers such as acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyethersulfone, and ethyl cellulose; There are polymers. When using a polymer soluble in an organic solvent, it may be used not only by being dissolved in the organic solvent, but also in the form of a latex dispersion.

The amount of binder used is 0.1 per m2 of support.
g to 50 g is preferred.

The support used in the present invention may be any material as long as it has good dimensional stability and can withstand the heat during recording with a thermal head, including thin paper such as condenser paper, glassine paper, polyethylene terephthalate, polyamide, etc. A heat resistant plastic film such as polycarbonate can be used.

The thickness of the support is preferably 2 to 30 μm, and the support may have a subbing layer for the purpose of improving adhesion with the binder, preventing transfer of the dye to the support, and preventing dyeing. good.

Furthermore, a slipping layer may be provided on the back surface of the support (the side opposite to the ink layer) for the purpose of preventing the head from adhering to the support.

The ink layer, ie, the heat-sensitive layer, used in the present invention is coated on a support or printed on the support by a printing method such as a gravure method. The thickness of the heat sensitive layer is 0.1μ in dry film thickness.
m to 5μ- is preferred.

Solvents for preparing the ink for the heat-sensitive layer include water, alcohols (e.g. ethanol, propatool), Cellosolve M (e.g. ethyl acetate), aromatics (e.g. toluene, xylene, chlorobenzene), ketones (e.g. (acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, dioxane), chlorinated solvents (eg, chloroform, trichlorethylene), and the like.

The heat-sensitive transfer material of the present invention basically comprises an ink layer on a support, comprising the dye used in the present invention and a binder;
That is, it is composed of a heat-sensitive layer, but may have a heat-fusible layer containing a heat-fusible compound as described in JP-A-59-106997 on the ink layer.

Furthermore, when the thermal transfer material of the present invention is applied to full-color image recording, a cyan ink layer containing a cyan dye, a magenta ink layer containing a heat-diffusible magenta dye, and a heat-diffusible yellow dye are formed on the support. It is preferable that three yellow ink layers are sequentially and repeatedly applied.

Further, in addition to the yellow magenta and cyan layers, an ink layer containing a black image forming substance may be further applied as necessary, so that a total of four layers are repeatedly applied in sequence.

The dye used in the present invention is a metal ion (preferably a complex metal ion, more preferably Cu"Ni", Zn"
, Coo) to form a metal chelate, a magentano hue can be obtained.

Therefore, in the image forming method using the thermal transfer recording material of the present invention, it is necessary that the image-receiving material contains a compound that supplies the metal ions (hereinafter referred to as metal source).

Furthermore, when the dye according to the present invention is applied to a heat-sensitive transfer material consisting of an ink layer and a heat-melting layer described in JP-A-59-106997, a metal source may be added to the heat-melting layer. Preferably, in the heat-sensitive transfer material having the above structure,
It is possible to form an image without adding a metal source to the image receiving material.

The metal source may be a salt of a complex metal, but it is also possible to use the metal sources described in Japanese Patent Publications No. 36-11535, Japanese Patent Application Laid-open Nos. 55-48210, and 55-129346.

When adding the metal source to the image-receiving material, it is usually added to the image-receiving layer of the image-receiving material.

The image-receiving layer is composed of a polymer such as polyester resin, polyvinyl chloride or a copolymer resin of vinyl chloride and other polymers (such as vinyl acetate), polyvinyl butyral, polyvinylpyrrolidone, or polycarbonate.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited only to these examples.

Example 1 [Ink Layer (Thermosensitive Layer)] A homogeneous solution ink containing the heat-diffusible dye used in the present invention and consisting of a mixture having the following composition was obtained.

Pigment compound Dye-110g Polyvinyl butyral resin 15g Methyl ethyl ketone 200 mρ [Preparation of transfer sheet] The ink containing the above heat-diffusible dye was placed on a support made of a polyethylene terephthalate film with a thickness of 5 μm using a wire paper. The amount of application after drying is 1. og/
(2) A layer containing a heat-diffusible dye was formed by coating and drying to prepare a heat-sensitive transfer material-1 of the present invention.

Similarly, in place of Dye-1 of thermal transfer material-1,
Thermal transfer materials-2 to 10 were prepared in the same manner as the thermal transfer material-1 except that the dyes shown in Table 1 were used.

[Thermal transfer image forming method] The heat-sensitive transfer sheet and image-receiving material obtained as described above are stacked so that the ink-coated surface of the heat-sensitive transfer sheet and the image-receiving surface of the image-receiving material face each other, and the heat-sensitive head is moved from the back side of the heat-sensitive transfer sheet. The image was recorded by hitting the target. As a result, a magenta image with excellent gradation was obtained.

Table 1 shows the maximum density of the obtained image, the hue (λ, 8, and λl/2) of the dye image, and the image stability (lightfastness).

The image-receiving material (recording material) used was photographic baryta paper coated with polyvinyl chloride containing the following metal source (applied amount: 5 g/+s'').

The recording conditions at this time are as follows.

Linear density of main scanning and sub-scanning: 4 dots/arm Recording power: 0.6 W/dot Heating time of thermal head The heating time was adjusted stepwise from 5 m5 ec to 0.5 m5 ec.

Image stability (light resistance) was measured by irradiating the sample with light for 96 hours using a xenon fade meter, and then showing the residual rate of image density for the sample obtained.

Metal source (applied amount: 1.5 g/m") Comparative dye A Comparative dye B υLIt+3 As is clear from Table 1, by using the present invention, a good hue (i.e., optimal λ=, :540 to 560 cm, and the absorption is sharp, resulting in an image with a good hue as a magenta image.)

Furthermore, since it has excellent chelate forming ability, it completely chelates even under thermal transfer conditions. Therefore, images with excellent light resistance are formed.

[Effects of the Invention] The present invention provides that a heat-sensitive transfer material using the dye represented by the general formula [I] not only has heat resistance, light resistance, and fixing property, but also has improved chelating property, heat diffusibility, and hue (an image created by a chelate dye with less undesired absorption and a narrow absorption band width) is formed. Further, the same effects as described above can also be achieved by using an image forming method using the heat-sensitive transfer material.

Claims (1)

[Scope of Claims] 1) A heat-sensitive transfer recording material comprising a heat-sensitive layer containing a dye represented by the general formula [I] on a support. General formula [I] [wherein, Furthermore, the ring may form a fused ring with another carbocycle or heterocycle. Y represents a halogen atom, an alkyl group, or an alkoxy group, and n is 0
, 1 or 2. R^1 represents a hydrogen atom or an alkyl group, R^2, R^
3 each independently represents a hydrogen atom, an alkyl group, or an aryl group, and R^2 and R^3 may be bonded to each other to form a 5- to 6-membered heterocycle. ] 2) A heat-sensitive transfer material having a heat-sensitive layer containing at least a dye represented by the general formula [I] on a support is heated from the back side of the support according to image information, and the image-receiving material is heated in the presence of metal ions. A method for forming a thermal transfer image, comprising forming an image using a chelate dye by reacting the dye with the dye. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [In the formula, The nitrogen-containing heterocycle may have a substituent, and the ring may also form a fused ring with another carbocycle or heterocycle, Y represents a halogen atom, an alkyl group, or an alkoxy group. , n is 0
, 1 or 2. R^1 represents a hydrogen atom or an alkyl group, R^2, R^
3 each independently represents a hydrogen atom, an alkyl group, or an aryl group, and R^2 and R^3 may be bonded to each other to form a 5- to 6-membered heterocycle. ]